Lubrication of alloy bearings



Patented Feb :20, 194.0

LUBRICATION F ALLOY BEARINGS Troy Lee Cantrell, Lansdowne, Pa., and James Otho Turner, Bartlesville, Okla, assignors to Gulf Oil Corporation, Pittsburgh, Pa., a-corporation of Pennsylvania No Drawing. Application June 9, 1936, Serial No. 84,387. Renewed August 5, 1938 This invention relates to improvements in the per and silver, of cadmium with copper and nickof sulphur and diaryl amines, particularly phenel, of lead with copper and nickel, etc. even under relatively high temperatures, speeds and pressures, this improvement of the mineral oil being efl'ected and its performance improved by the presence therein of asmall amount of phenthiwhen subjected to conditions of operation, by

maintaining between bearing surfaces, one of which is an alloy formed chiefiy of a metal consisting of the classes of 'cadmium and copper, a

film of lubricating oil which initially produces an i efiectrve lubricating action but which would nor-- mally tend to corrode the aforesaid alloy and maintaining the effectiveness of the lubricating oil by incorporating therein a reaction product of a di-aryl amine and sulfur, specifically phenthiazine, in a small amount but suflicient proportion to substantially retard the said corrosion; all as more fully hereinafter set forth and claimed.

Recent developments in the design of mechanical equipment for generating and transmitting power, and particularly in the automotive field, have necessitated new bearing metals with special properties in this relation. Among these new bearing materials are binary and ternary alloys 0 of the metals mentioned above. Cadmium-silvercopper, cadmium-nickel-copper, copper-leadnickel, etc., alloys are in use. One ternary alloy currently used in automobile engines is an alloy of cadmium with minor amounts of both silver and copper. Under the conditions imposed by modern engineering design, these new alloy bearings are commonly subjected to more severe operating conditions than were usual in the older art: to higher bearing loads, higher rubbing speeds and higher temperatures of operation. It is found that in actual use under these conditions there often develops quite serious destructive action on the bearing surface by mineral lubricating oils, even by those standard commercial oils giving particularly good results with the older bearing metals under the earlier operating conditions. The destruction of the bearing metal probably results from action of deterioration products developed in the oil. An object achieved inthe present invention is the production of lubricating oils im- 5 proved for these newer conditions of use and which are characterized by reduction or eliminationof destructive action on the newer bearing metals by deterioration products in the oil.

We have discovered that the reaction products 0 thiazine, are capable of achieving the objects of the present invention. By adding small amounts of such products to the mineral oil or lubricant, we obtain lubricating compositions which satis- 15 factorily lubricate the said alloy bearings. Incorporated in mineral 011, they retard destruction of the bearing metal. Also, the film strength of thelubricant is increased, these compounds imparting extreme pressure characteristics to the 20 oil. The character and amount of added improvement agents, here employed, are such that the advantageous properties oi the oil, such as viscosity, gravity, color, etc., are not substan tially altered. Certain properties of the lubri- 25 cant are improved withoutsacrifici ng the other desirable properties.

We obtain improved mineral oils and lubricants suitable for lubricating bearings under a wide range of service conditions. The new com- 30 pounded lubricant satisfactorily lubricates the new alloy bearings even under high unit pressure, high bearing speeds and. high operating temperatures. When prepared from. suitable motor oils, the present improved compositions 35 are'excellent lubricants for the modern automobile engine. They satisfactorily lubricate the bearings without any corrosion of the special alloys now used, even when there is a free circulation of air. 40

Ordinarily between 0.10 and 0.50 per cent, by weight on the oil, of these agents is sufficient to produce a satisfactory lubricant. However, the

particular proportions depend upon the particular agent and lubricating base employed and the 46 particular type of lubricant desired. The less stable lubricating oils require the higher percentage of phenthiazine.

When the larger amounts of these agents are employed, marked extreme pressure character- 50 istics are imparted to the lubricant in addition to retarding its destructive action on alloy metal bearings; the film strength of the lubricant beingincreased by as much as 50 to per cent as stated ante. Thus the addition of these agents 55 the condition of the bearing shell are determined. In determining the loss in weight the bearing shell is washed free of oil and dried before weighing. This test will hereinafter be referred to as our standard laboratory test.

When determining the effectiveness of various improvement agents the usual procedure is to run a blank" test simultaneously with the oil composition being tested, employing for that purpose a sample of the untreated oil.

In such tests it is advantageous to employ commercial bearing shells. These shells comprise a suitable metal backing faced with the alloy bearing metal. In the above test, the air is bubbled against the alloy bearing face. In this way, theactual bearing face is subjected to severe deteriorative conditions. By comparison of the results of such tests with actual service tests, we have found them to be in substantial agreement as to the suitability of particular lubricants.

In testing our lubricants, we have employed, among others, bearings of the following approximate composition:

Such alloys are used in the tests of illustrative improved lubricants given post. In such tests the loss in weight, while not extremely high when expressed as per cent loss, is nevertheless very significant, as the bearing shells used have an alloy facing of only .008 inch to .012 inch. thickness on a highly resistant backing and the observed losses in the reported tests often represent a loss of the order of ten per cent of the alloy facing.

The specific examples and tests' given post are illustrative of detail embodiments of the present invention.

Example 1.Into a suitable vessel there are introduced 200 pounds of diphenyl amine. 'The vessel is heated to a temperature sumcient to melt the amine and then 64 pounds of flower of sulfur (approximately 1 mol of sulfur to 2 mols of amine) are gradually added to the molten amine. Then the mixture. is brought to 250 F. and agitated until the sulfur is dissolved. While continuing the stirring 132 pounds of anhydrous aluminum chloride (5 per cent of catalyst by weight on the mixture) is added. Then the,

mixture is gradually heated to 350 F. and maintained'at that temperature and agitated until the reaction is substantially complete, about 8 hours being required with the reaction mixture employed.

The reaction products are cooled and the solid material so obtained is powdered. This powder is'extracted with water to remove the aluminum chloride and other water soluble impurities. The extracted material is thendried in 5 ourrent-of warm air. The dried product is a greenish-gray powder having a melting point or 330 F. It analyzed as follows:

Per cent Car 72.4 Nitrogen 7.25 Hydrogen 4.52 Sulfur--- 15.20

This dried, extracted reaction product is useful as an improvement agent for mineral oils. If desired it may be further purified by recrystallization from ethyl alcohol. The crystallized material so obtained has a melting point of 350 F. The purified product is advantageous in making certain improved lubricants, such as motor oils. wherein ahigher degreeof purity is desired.

Example 2.Into a suitable vessel there are introduced 1000 gallons (7200 lbs.) of Pennsylvania motor oil SAE\ grade and the oil warmed to 160 F. Then 14.4 pounds of phenthiazine (0.20 per cent by weight on the oil) are gradually added and the mixture agitated until a uniform blend is obtained; about 1 hour being required. The improved-motor oil is then cooled and is a finished product. In agitating the mixture, ordinary mechanical agitators may be employed or a current of air may be passed through the warm mixture to produce uniform blending.

The properties of the original and improved motor oil are as follows:

Table A Improved original 9 lubricant Gravity: "A?! 33.0 32.9 Viscosity SUV- 40.2 46.2 420 420 490 490 0 0 P 1.25 1.75 Carbon residue: percent-.. 0. 02 0.02 Copper strip test Satisfactory s I From the above table, it is clear that the addition of phenthiazine does not substantially change the ordinary properties of the oil. However, the improved lubricant obtained is sa factory for lubricating the newer alloy bearings. When tested by the standard laboratory test given ante, using a commercial bearing shell faced with the cadmium alloy' (0-8 7610), the following results were obtained in a 48 hour test run.

Table 8 1 Bearing mu weight-- Original oil m x cant Grams Grams Before test 21. 8072 27. 0445 Aflel some 21.0450

.Total change -f. 1.12m +0.00%

CommenhBem-lngappeemnce (ef e test)- B a d 1 Good.

I pitted.

i From the above results, "the beneficial eflect of the 'phenthiazine 'as an improvement agent -for the oil is quite apparent. This improved lubricant when'tested in an automobile engine equipped with like bearings was highly s'atis-.-

factory and no corrosion of the bearing was observed after a" severe test run. Thus the standard test and actual service test gave similar results.

Example 3.-Employing the procedure of Example .2, using 0.50 per cent of phenthiazine and a SAE 20 grade motor oil in lieu of the particular materials in Example 1, another improved motor-oil is obtained. It islikewise satisfactory for lubricating the newer alloy bearings without substantial deterioration of the bearing metal. when likewise subjected to the standard laboratory test the following results were obtained:

tice other embodiments may be used. That is, the percentage of improvement agent to the lubricant to improve it may be varied, as indicated, according to the particular properties desired in the final lubricant and the lubricating base used. Likewise, the lubricating base itself may be selected according to the type of the final lubricant to be produced.

As stated ante, the incorporation of these reaction products with the lubricating base produces several improvements in the final lubricant without deleteriously aflecting the desirable properties. While the exact reasons for the improvements obtained are not fully known, we are satisfied with observing and utilizing the actual improvements obtained by adding and incorporating these improvement agents with commercial lubricants.

What we claim is:

1 A method of lubricating bearing surfaces in internal combustion engines when subjected to conditions of operation which comprises maintaining between bearing surfaces, one of which is an alloy formed chiefly of a metal selected from the class consisting of cadmium and copper, a film of lubricating oil which initially produces an eiiective lubricating action but which would normally tend to corrode the aforesaid alloy, and maintaining the effectiveness of the lubricating oil by incorporating therein a reaction product of a diaryl amine .and sulphur in a small but sufiiclent proportion substantially to retard the corrosion.

2. A method of lubricating bearing surfaces in internal combustion engines when subjected to conditions of operation which comprises maintaining between bearing surfaces; one of which is an alloy formed'chiefly of a metal selected from the class consisting of cadmium and copper.

. a film of lubricating oil which initially produces an efiective lubricating action but which would normally tend to corrode the aforesaid alloy, and maintaining the efiectiveness of the lubrieating oil by incorporating therein phenthiazine in a small but suflicient proportion substantially to retard the corrosion.

TROY LEE CAN'I'RELL. JAMES OTHO TURNER. 

